evolution
revere | March 29, 2009If it's true that atheism is a "religion" because it has a "non-belief system," there are a helluva lot of atheists out there, since there are a lot of religions and most people believe in at most one of them. Or as one wag put it, "We are all atheists. It's just that I believe in one less god than you." That's a fairly trivial observation and not the main point of this week's Sermonette, which is about Evolution -- in particular, The Origin of Specious. But most people will have no trouble making the inference:
evolvingthoughts | March 28, 2009A dozen or so years ago, or maybe more, I was heading up the communications section of The Walter and Eliza Hall Institute of Medical Research in Melbourne, when I employed a young biology graduate as a graphics guy to do medical graphics. This he did for a while, until he started playing with three-dimensional graphics software. He did some animations of cell surface signalling molecules, and of malaria parasites, and cancer cells, and took them to the director, and suggested that we set up an animation unit within the department.
This we did, and within a short while, Drew Berry had managed…
edyong | March 28, 2009
Animals have distinct personalities and temperaments, but why would evolution favour these over more flexible and adaptible mindsets? New game theory models show that animal personalities are a natural progression from the choices they make over how to live and reproduce.
Any pet owner, wildlife photographer or zookeeper will tell you that animals have distinct personalities. Some are aggressive, others are docile; some are bold, others are timid.
In some circles, ascribing personalities to animals is still a cardinal sin of biology and warrants being branded with a scarlet A (for…
clock | March 27, 2009Check out the show's web page:
Fifteen thousand years ago North America was like the Serengeti on steroids, with mega-creatures roaming a continent teeming with incredible wildlife. But then, in a blip of geologic time, somewhere between 15 and 35 magnificent large types of animals went extinct. In a television exclusive, NOVA joins forces with prominent scientists to test a startling theory that may finally explain the Last Extinction, on Tuesday, March 31 at 8pm ET/PT on PBS (check local listings). The program features scientists representing all sides of this debate.
evolvingthoughts | March 26, 2009It's true! Dinosaurs still exist. John Conway dissected a Rhamphorhyncus, and drew what he saw, here.
I had "dinosaur" in the title but as Chris points out, that's a bad error, like calling a mammal a turtle.
Damn, I'm not having much luck. Not a pteranodon then...
amillikan | March 26, 2009Over the past three days, the Texas State Board of Education has heard over 50 testimonies debating a proposed amendment to reinstate the requirement of teaching the "strengths and weaknesses" of the theory of evolution in the statewide science curriculum. The proposed regulation, which has provided creationism a place in the classroom in the past, alarmed scientists not only for its potential repercussions in Texas, but because of the state's large textbook market as well, which forces textbook authors to bend to the state's curricula. To their relief, the bill failed this morning in a…
evolvingthoughts | March 25, 2009Some links and issues I have come across lately.
Those who read this and my other blog know that I am deeply opposed to internet censorship. Recently, Wikileaks put up a leaked list supposed to be the list being used in Australian trials of what will be a mandatory blacklist of URLs. First the minister said it wasn't the list, then he said it had some similarities, and now he says it's substantially the right list but there have been edits, but that's not my point. Now, in Germany, a Wikileaks host has been raided at the behest of a German minister. It's even possible that the Australian…
razib | March 25, 2009Nick Wade in The New York Times has a piece on a review on the relationships between male competition, signaling and sexual selection. If the topic interests you I strongly recommend Animal Signals, John Maynard Smith's last book.
amillikan | March 25, 2009A new paper published in Genome Research provides the most comprehensive scan to date of the genetic signatures of natural selection resulting from the last 10-40,000 years of human evolution, with some intriguing results. The results show strikingly different patterns of selection in distantly related human populations, suggesting that different human groups have adapted to their environments in different ways. Many of the regions seen to be most subject to selection contain genes of unknown function—or no genes at all—but regions linked to increased risk of type 2 diabetes showed a…
grrlscientist | March 25, 2009tags: evolutionary biology, speciation, species flocks, molecular phylogeny, behavioral ecology, Synodontis species, squeaker catfish, cuckoo catfish, Lake Tanganyika, peer-reviewed paper
The Cuckoo Catfish, Synodontis multipunctatus [Siluriformes: Mochokidae].
This is the only fish that is a known brood parasite.
This is one of the species included in this newly-published study.
Image: orphaned.
One of the groups of fishes that I worked with as an aquarist for nearly my entire life are the synodontids, often known as "squeaker catfish" for their ability to make high-pitched sounds.…
razib | March 24, 2009Genetic Future's summary of Signals of recent positive selection in a worldwide sample of human populations is an excellent complement to mine. Highly recommended.
evolvingthoughts | March 24, 2009Anthony Grayling, who does a really interesting review column in the Barnes and Noble Review, entitled "A Thinking Read", has a piece on Jerry Coyne's book Why Evolution is True. This saves me having to read it and review it for you myself.
The column title is a pun on Blaise Pascal's statement that "Man is but a reed, the most feeble thing in nature, but he is a thinking reed". A pun which I wish I had come up with.
edyong | March 24, 2009Be it in sports or comedy, they say that timing is everything. In evolution, it's no different. Many of the innovations that have separated us from other apes may have arisen not through creating new genetic material, but by subtly shifting how the existing lot is used.
Take our brains, for example. In the brains of humans, chimps and many other mammals, the genes that are switched on in the brain change dramatically in the first few years of life. But Mehmet Somel from the Max Planck Institute for Evolutionary Anthropology has found that a small but select squad of genes, involved in the…
razib | March 23, 2009Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario:
The interpretation of genetic evidence regarding modern human origins depends, among other things, on assessments of the structure and the variation of ancient populations. Because we lack genetic data from the time when the first anatomically modern humans appeared, between 200,000 and 60,000 years ago, instead we exploit the phenotype of neurocranial geometry to compare the variation in early modern human fossils with that in other groups of fossil Homo and recent modern humans.…
edyong | March 23, 2009Sixty-five million years ago, life on Earth was sorely tested. One or more catastrophic events including a massive asteroid strike and increased volcanic activity, created wildfires on a global scale and dust clouds that cut the planet's surface off from the sun's vital light. The majority of animal species went extinct including, most famously, the dinosaurs. The fate of the planet's plants is less familiar, but 60% of those also perished. What separated the survivors from the deceased? How did some species cross this so-called "K/T boundary"?
Jeffrey Fawcett form the Flanders Institute for…
grrlscientist | March 22, 2009tags: evolutionary biology, mate choice, sex determination, genetic compatibility, behavioral ecology, Gouldian Finch, Erythrura gouldiae, peer-reviewed paper
The three color morphs of Gouldian finches, Erythrura gouldiae.
Image: Sarah Pryke, Macquarie University.
Gouldian finches, Erythrura gouldiae, are small cavity-nesting passerines that are endemic to open savannahs adjacent to mangrove swamps in northern Australia. These finches eat a variety of native grass seeds, but to meet the increased energetic and nutritional demands of rearing chicks, they primarily eat insects when…
evolvingthoughts | March 21, 2009There are a lot of folk who think they have a handle on how to communicate science to the general public, and a lot of folk, mostly scientists, who think nobody else does. But I was reading Carl Zimmer's twittering today, about Rebecca Skoot getting a column gig for a new magazine devoted to issues of interest to women, Double X. It hit me that science journalism is not dying, it is having to adapt to a new business model.
Traditional media made its money from advertising and sales. It used a broadcast model of publishing - a single source (the printing presses or the transmitters) to many…
edyong | March 21, 2009
Walking on two legs, or bipedalism, immediately sets us apart form other apes. It frees our arms for using tools and weapons and is a key part of our evolutionary success. Scientists have put forward a few theories to explain how our upright gait evolved, but the 'savannah theory' is by far the most prolific.
It's nicely illustrated by this misleading image that has become a mainstay of popular culture. It suggests that our ancestors went from four legs to two via the four-legged knuckle-walking gait of gorillas and chimps. Dwindling forests eventually pushed them from knuckle-walking to a…
pharyngula | March 20, 2009I'm not going to say much about this since Ed Yong has an excellent write-up, but a new feathered dinosaur has been discovered, called Tianyulong. As you can see in this image of the fossil, it was bristling with a fuzz of thin fibers — proto-feathers.
(Click for larger image)a, Main slab of the holotype (STMN 26-3). b, Broken slab. The scale bar in b refers also to a. c, Close-up of skull and mandible. d, Interpretive drawing of skull and mandible. e, Close-up of dentition. Abbreviations: a, angular; aof, antorbital fossa; ca, caudal vertebrae; cv, cervical vertebrae; d, dentary; dv, dorsal…